Listening-detector for telephone-lines.



, B. & 0. BURGENER. LISTENING DETECTOR FOR TELEPHONE LINES.

APPLICATION FILED JAN. 8, 1.911.

Patented Feb. 6, 1912.

TO LINE To LINE.

WITNESSES ERNEST BURGENER, OF WELLESLEY, AND CHRISTIAN BURGENER, F LINWOOD,

ONTARIO,

CANADA.

LISTENING-DETECTOR FOR TELEPHONE-LINES.

To all whom. it may concern:

Be it known that we, ERNEST BURcnNER,

of VVellesley, and CHRISTIAN Bnncmvnn, of

Linwood, in the Province of Ontario, Canada, have invented certain new and useful Improvements in Listening-Detectors for Telephone-Lines, of which the following is a. specification.

The object of our invention is to devise simple and cheap means for detecting improper listening in telephone systems in which asingle line is employed by a number of individuals.

We attain our object by a signal sounding a rrangcment which may be briefly described as follows :Adjacent the transmitter of the telephone is located an electro-magnetic buzzer or other signal sounding device and an electro-motor device actuating suitable means for making and breaking the circuit. of the buzzer to causethe sounding of a predetermined signal. The circuit of the motor device is .closed at starting by the removal of the receiver from the telephone hook. The device is also arranged so that the electro-motor device is again operated to sound a signal when thereceiver is put back on the hook. The parties who are legitinmtely using the line can hear these signals and as each telephone will have a different. signal any il'nproper listening is at once detected and the listener identified.

Figure 1 is a diagranunatical view of the installation. Fig. 2 is a horizontal longitudinal section of the signal device. Fig. 3 is a cross section of the same. Fig. 4is a horizontal longitudinal section of the double switch. Fig. 5 is a cross-section of the same. Fig. (3 is a sectional detail of a friction device used in the operating mechanism for the double switch and "signal device.

In the drawings like figures of reference indicate corresponding parts in the different figures.

buzzer or other electric sounding device and 2 1s the circuit of the said buzzer which 1ncludes the battery or other source of current at is a signal device. While any device the purpose of our invention, we prefer the arrangement shown diagrammatically in Specification of Letters Patent.

' Patented Feb. 6, 1912.

Application filed January 3, 1911. Serial No. 600,532.

i Fig. 1 and constructively in Figs. 2 and 3.

l The device comprises a tube 5 within which are located the metal plates 6 and 7 suitably supported, and connected with the wires2 of the buzzer circuit. Electrical contactbetween these plates is formed by means of a globule 8 of mercury. The tube isso proportioned relative to the plates that the mercury when the tube is tilted endwise may run down one side of the tube and then back along the other side when the tube is tilted in the reversedirection thus making contact alternately between opposite sides of the plates 6 and 7. A channel 11 extends down each side and around the ends of thetube and in this channel the mercury will circulate as the tube is oscillated. By notching one or both ofthese plates the buzzer circuit. may be alternately made and broken in such a way as to sound a signal. The notches are preferably cut as indicated in Fig. 2, so that the same signal is sounded when the back along the other side. The signal device is actuated through the medium of constructions we will now describe. The signal device is suitably pivoted at 9 on a suitable stationary part and its other end ispivotally connected by means of a link 10 with an arm 11 fulcrumed at 12 on a suitable stationary part. armature 13 of an electr'o-magnet' of which switch 17. The starting switch 16 comprises a movable contact finger 18 and a fixed contact 19. The telephone book 20 engages this finger 18 and when the hook is up moves it over to engage the fixed contact 19 closing the circuit of the electro-magnet 14.

The stopping switch is preferably arranged as follows: 21 is a tube pivoted at 22 on a suitable stationary part and pivotally connected at its other end with the. link 10. Referring particularly to Fig. 1, 1 is a In the tube is located a globule -23 of mercury, the tube being preferably shaped at its lower side to form a trough for the mercury to run in, see Fig. 5. Two contacts 2 1 are located within the tube connected with the lead wires 25 extending through the glass "parts are shown in Fig. 1 in an intermediate t position. If the circuit of the electro-magl net 14. be closed,'by/lifting the receiver from This arm 11 is connected with themercury runs down one side as when it runs 15 is the circuit, and in this circuit is locatcd the starting switch 16 and a stoppingv and suitably connected with the wires 15 of I the circuitof the electro-magnet 14. The

its hook the electro-magnet 14: will be energized and the arm 11 rocked to incline the signal device 4 and the switch tube 21 toward the right. This causes the sounding of a signal as the mercury globule'. 8 travels down the edgesof the plates 6 and-7. The

-signal ceases, of course, as soon as the mercury -globule reached the end of the tube. The instant after. the tubes have been rocked the circuit of the electromagnet 14 is broken by the mercury globule 23 in the switch tube 21 rolling away from the contacts 2t and the denergizin'g of the magnet leaves the arm to the arm so that it will tendto stay inthe position to which it has been moved. For this pur ose we show the fulcrum 12 of the j arm 11 ormed as a threaded pin secured to the post 26'. On the pinis threaded the nut 27 and between theend of the arm 11 we lace a, coil spring 28. The frame is thus rictionally held against the post 26 and the degree of friction may regulatedby means of the nut 27.

In order to return the parts to the normal position and incidentally sound a second signal, when the receiver is replaced on its.

' hook we provide the followingarrangement 2 The starting switch 16 is provided with a. back contact 29 connected with the circuit 30- of an electro-magnet 31 arranged diametrically opposite the electro-magnet 14 so as to attract the same armature 13.

the part of the circuit 15 between the battery 3 and the movable contact finger 18of the starting switeh. The contact finger 18 is :circuit 30 of the electro-ma'gnetBl; This circuit 30 also includes a stopping switch 32. This is precisely similar to the stopping switch 17, but is arranged at the other end of switch li-UbQ2-1, EWO suitable contacts 38 being provided within the tube, connectedby meansofthe lead wires 3a with the wires of the circuit 30. When the signal tube and switch tube were inclined to the right as previously described the mercury globule 23 rclled'down the tube and closed the circuit of the electro-magnet2 1 at this point.- As soon, therefore, as the'fcircuit was closed at the starting switch, as previously described, the el'ectro magnet 31 would be energized and the arm 11 rocked to restorethe switch tube and signal tube to their original posithe signal tube, hereinbefore described, but

tube '21.

37 suitably supported within the tube and (I Part of the circuit of the electro-magnet 31 is formed by.

also closes the stopping switch 17 of the cir 4 I cuit of the electro-magnet 14 so that the device is ready for operation to again send a signal as soon as the circuit of the electrowire. -As the successful operation of our apparatus depends on thetransmission of signals whether the receiver is on or off its hookit'is necessary to provide some means for. connecting the transmitter to line when theJsignal apparatus is in operation. In Fig. 1 we indicate the transmitter at 35 and show it connected with the wire 36 which maybe connected to line. This wire 36 is connected with a special switch in the switch This comprises two parallel'bars extending within a short distance of the contacts at each end of the tube. Lead wires 38 are connected with these bars and serve for rolls from one end of the tube to the other, and this connects the transmitter to line as long as a signal is being given as the bars 37 are suitably proportioned to maintain this connection of the transmitter to line as long as the mercury gl'obule 8 is making signal contactsbetw een the plates 6 and 7. of the signal device. As soon as the mercury globule 23 reaches either end of the tube it breaks connection between the bars 37 and leaves-the telephone in its normal condition.

InFig. .1 we indicate diagrammatically, means for establishing a talking circuit when the receiver is lifted from the'hook 20. A wire 39' is shown connected with the upper hook contact and with the transmitter 35,

and a wire 40 is shown connected with the hook and the wire 36 at the line side ofthe switch 37. When the hook engages the upper contact as it does when the receiver is lifitlcdjL ofi the'hook, a talking circuit is establis e From the above description it will be seen that wehavedevised an anti-listening device WhlCh will send a signal whenever the receiver ISTBIIIO'VBd from the hook and which cannot in any way be manipulated-to stop 1. In a telephone listening detector the combination of a buzzer and its circuit; a

contactmaker and breaker in the buzzer circuit -fo'rming a signal device; an electromotor device and llZS'QlIClllt for actuating the signal device; a telephone book; and a starting switch in the circuit of the motor device actuated by the telephone hook on the removal of the receiver. v

2. In a telephone listening detector the combination of a buzzer and its circuit; a contact maker and breaker in the buzzer circuit forming a signal device; an electromotor device and its circuit for actuating the signal device; a telephone hook; and a starting switch in the circuit of the motor device actuated by the telephone book on the removal of the receiver; and means .arranged to maintain a break in the buzzer circuit as soon as the signal has been sounded.

3. In a telephone listening detector the. combination of a buzze' and its circuit; a contact maker and breaker in the buzzer circuit forming a signal device; an electromotor device and its circuit for actuating the signal device; a telephone hook; a starting switch in the circuit of the motor device actuated by the telephone hook on the removal of the receiver; means arranged to maintain a break in the buzzer circuit as soon as the signal been sounded; and means whereby the return of the receiver to the hook causes a second actuation of the signal device.

4. In a telephone listening detector the combination of a buzzer and its circuit; a

contact maker and breaker in the buzzer circuit forming a signal device; an electromotor device and its circuit for actuating the signal device; a telephone hook; a starting switch in the circuit of the motor device actuated by the telephone hook on the removal of the receiver; and means for antomatically breaking the electro-motor circuit as soon as the signal device has been sufficiently actuated to causethe giving of a signal.

5. In a telephone listening detector the combination of a buzzer and its circuit; a contact maker and breaker in the buzzer circuit forming a signal device; an electromotor device and its circuit for actuating the signal device; a telephone hook; a starting switch in the circuit of the motor device actuated by the telephone book on the removal of the receiver; a second electro-motor device and circuit adapted to actuate the signal device; and a starting switch in the circuit of the second electro-motor device actuated by the telephone hook on the replacing of the receiver on the book.

6. In a telephone listening detector the combination of a buzzer and its circuit; a

contact maker and breaker in the buzzer circuit forming a signal device; an electro-- motor device and its circuit for actuating the signal device; a telephone hook; a starting switch in the circuit of the motor device actuated by the telephone book on the removal of the receiver; a normally open circuit connecting the transmitter to line; and a switch actuated by the electro-motor device to close the circuit during the sounding of a signal.

T. In a telephone listening detector the combination of a buzzer and its circuit; a contact maker and breaker in the buzzer circuit forming a signal device and movable to operate in either of two directions; an electro-motor device and its circuit for actuating the signal device in one direction; an electro-motor device and its circuit for actuating the signal device in the other di rection; a-(louble starting switch adapted to close the circuit of one electro-motor device and open the other, and vice versa; and a doubleswitchactuated by the electro-motor devices whereby the actuation of either one of'the electro motor devices causes. as far as said switch is concerned. the breaking of said elcctro-motor circuit and the closing of the circuit of the other electro-motor device.

8. In a telephone listening detector the combination of a buzzer and its circuit; a contact maker and breaker in the buzzer circuit forming a signal device and comprising a tiltable trough, a globule of mercury in the trough. and two separated metal platesconnccted in the buzzer circuit and shaped to make and break the buzzer circuit as the mercury rolls between them; an

electro-motor device and its circuit for actuating the signal device; and a starting switch in the circuit of the motpr device actuated by the telephone hook on the removal of the receiver.

9. A signal device for the purpose described comprising a tube; a mercury globu'le therein; two separated metal plates having lead wires connected therewith and shaped at the adjacent edges at' both sides to make and break contact with the mercury globule. the tube being channeled so that the globule will roll along one side and then back along the other as the tube is oscillated.

Dated at Berlin this 27 day of Dec. 1910.

ERNEST BURGENER. CHRISTIAN BURGENER. Signed in the presence of C. W. CHAPMAN, Miss C. ScnwErrzER. 

